The present invention relates in general to dental implants, and in particular to a new and useful dental implant hole guide arrangement which provides a dentist with an accurate guide to follow for drilling the critical initial pilot hole for a dental implant into an edentulous or toothless jaw bone ridge, so that the hole is aligned on an acceptable axis in the patient's jaw bone.
Since 1981, dental root form implants have become a standard procedure for replacing missing teeth. Unlike other dental procedures such as crown and bridge work, root canals and the like, which utilize at least part of the original tooth as a foundation for the tooth replacement, implants require the drilling of holes directly into the bone of the jaw.
Although the dental implants have many benefits, particularly where a patient is missing teeth over large portions of the mouth, various complications can follow implant placement, especially to adjacent teeth. The bone may be overheated during implant surgery for example and this can devitalize an adjacent tooth. Endodontic lesions can also form which compromise the implant fixture by preventing integration of the bone around the fixture (Osseointegration) causing loss of the implant.
Another problem involves patient with no teeth or so called edentulous patients.
Within the confines of the mouth, it is very difficult to accurately align a dental bur for drilling the crucial initial pilot hole of about 2 mm in diameter. The pilot hole must be drilled along an acceptable axis into the jaw bone which both avoids any critical structures in the bone such as nerves, blood vessels and the like, but also avoids intersecting the root of an adjacent tooth which may not be apparent without x-rays. Even with x-rays, however, it is difficult for a dentist to accurately align the bur without some help.
U.S. Pat. No. 5,888,065, invented by the present inventor, discloses a dental implant guide arrangement that is capable of accurately guiding a bur for drilling a pilot hole for a dental implant. The arrangement includes a pair of jaws which engage lingual and buccal surfaces of a tooth and are held to each other by a fixing mechanism, such as a screw. A guide member extends from one of the jaws and has a semi-cylindrical guide that is parallel to an acceptable axis for the pilot hole. The bur can be guided along the guide for accurately drilling the pilot hole.
A limitation of the invention in U.S. Pat. No. 5,888,065, however, is that the patient must have at least one tooth adjacent each area selected to receive an implant. Since it is customary to install from one to three implants in each quadrant of a patients mouth if natural tooth structures are not present, this poses a difficult problem for patients with no teeth. Also see the inventor's U.S. Pat. No. 6,062,856.
One very complex and time consuming technique for properly aligning the initial implant hole for a patient is disclosed in U.S. Pat. No. 5,015,183 entitled LOCATING DEVICE AND METHOD OF PLACING A TOOTH IMPLANT. According to this method, a stent comprising a negative impression of a patient's teeth in the vicinity of the implant is taken. Multiple x-ray opaque strips are placed in the negative impression and an oblique x-ray is taken. This x-ray is used as a diagnostic tool for the patient's jaw structure to help plot the trajectory of an implant fixture in the jaw.
Another problem associated with the use of a stent is that when a surgical stent is fabricated from an alginate jaw impression, as is commonly done, the registration of the surface jaw tissue does not always reflect the underlying topography of the jaw bone where the implant is to be placed.
In any case, once an acceptable initial implant hole is formed in the jaw, subsequent holes can be produced by using the initial hole as a guide. This is when multiple implants are to be installed. See, for example, U.S. Pat. Nos. 5,741,133 and 5,302,122. Other techniques and apparatuses for drilling holes in the jaw bone are disclosed in U.S. Pat. Nos. 4,787,848 and 4,998,881. A need remains, however, for a simple and effective tool which can be used particularly by general dentists to permit them to produce the initial pilot hole along an acceptable axis in a patient's jaw bone. Once the initial bore is made, it can be enlarged to the required final diameter, generally about 4 mm, using ever increasing bur sizes. Once the initial hole is drilled, the enlargements are easily made using the initial hole as the guide. The present invention provides a way of making that critical initial hole.
U.S. Pat. No. 5,842,859 discloses a simple implant hole drilling guide but with only an open guide surface but no encircling guide bore for the drill. U.S. Pat. No. 5,833,693 uses a circular but not cylindrical drill guide bore and a length adjustable block with a downwardly extending hole engaging pin and an upwardly extending handle.
Also see U.S. Pat. No. 4,325,373 for a guide with a hole engaging pin.